Studies will be continued in the following areas of basic and applied viruses. 1. to detect and characterize previously unrecognized viruses. 2. to determine the etiologic role of viral agents, including those in latent, persistent, chronic or altered states of infectivity, in various acute and chronic syndromes of uncertain cause. 3. to identify and characterize various viral antigens and antibodies and their interactions, and to elucidate the processes of viral replication and virus host-cell interaction at the cellular, molecular and ultra-structural level. 4. to adapt findings from these studies to develop and evaluate new or improved laboratory diagnostic procedures for use in clinical virology. 5. to apply viral laboratory technology in joint laboratory/field investigations to elucidate the epidemiology and natural history of selected viral diseases, especially those due to arboviruses, vector-borne and zoonotic agents.